The SMDN0099 disc neodymium magnet is made from high-performance N52 NdFeB, with Black Nickel coating. The dimension of this item is 1/2″ dia. × 1/4″ thick, magnetized through thickness, with the tolerance of ±0.004″ × ±0.004″. The weight of this super strong neodymium magnet is 0.0133125 lbs. It can pull up to 13.47 lbs steel. And the surface field is up to 5233 gausses.